9. Gas-dynamic simulation of the supersonic stream in the pulsed wind tunnel

Annotation: A promising experimental bench – a shock wind tunnel was put into operation at Yuzhnoye SDO. The shock wind tunnel is designed to simulate the incident flow during rocket flight at high supersonic and hypersonic velocities. To solve actual design problems facing Yuzhnoye SDO, it was necessary to expand the range of velocities under investigation in a shock wind tunnel by low supersonic Mach numbers (Mа=1.5; 2; 3). As a result of this work, a modernized configuration of the shock wind tunnel was developed, which allows simulating flow parameters at low supersonic velocities. The results of aerodynamic experiment performed in the modernized shock wind tunnel, which are close to full scale ones, can be obtained using as much data on peculiarities of supersonic flow formation in it as possible. Therefore, the study of the distribution of Mach numbers profiles in the working section of the modernized shock wind tunnel at low and high supersonic velocity was chosen as the main line of research. The results of the research presented in the article are based on the use of numerical simulation methods, as well as data obtained experimentally. As a result of gasdynamic simulation of a supersonic flow conducted for the nozzle Mа=4 and the nozzle Mа=2, the calculated and experimental data on the distribution pattern and field values of Mach numbers in the working section of the tunnel were obtained. A comparative analysis was carried out. The boundaries of the region of equal velocities, within which the condition of quasistatic supersonic flow is satisfied, and the lifetime of the operating mode for the selected nozzle type were determined. At the flow from the nozzle Mа=2, a peculiarity was revealed in the distribution pattern of Mach numbers fields associated with the appearance of “blocking” effect of the supersonic flow. The methods for eliminating the effect of flow “blocking” at low supersonic velocities are proposed.